Always use the current branch of edited chunks' reposbaserock/richardmaw/always-use-current-branch

If you checkout a different branch, or even no branch at all with a
dangling head (such as bisecting) then morph will use that, rather than
what "ref" is set to in the morphology.

Push and temporary build branch creation avoidance still assume that the
ref in the edited chunk repository matches the ref in the morphology, so
if you checkout a different branch and everything is committed, it will
assume there's no local changes and build what the ref points to.

3 files changed, 46 insertions, 4 deletions

diff --git a/morphlib/buildbranch.py b/morphlib/buildbranch.py
index 885f5cf8..067ae55e 100644
--- a/morphlib/buildbranch.py
+++ b/morphlib/buildbranch.py
@@ -125,14 +125,18 @@ class BuildBranch(object):
 
         sb_info = {}
         for gd, (build_ref, index) in self._to_push.iteritems():
-            repo, ref = gd.get_config('morph.repository'), gd.HEAD
-            sb_info[repo, ref] = (gd, build_ref)
+            if gd == self._root:
+                continue
+            morph_name = gd.get_config('morph.chunk-name')
+            sb_info[morph_name] = (gd, build_ref)
 
         def filter(m, kind, spec):
-            return (spec.get('repo'), spec.get('ref')) in sb_info
+            name = (spec['name'] if 'name' in spec else spec['morph'])
+            return name in sb_info
         def process(m, kind, spec):
+            name = (spec['name'] if 'name' in spec else spec['morph'])
+            gd, build_ref = sb_info[name]
             repo, ref = spec['repo'], spec['ref']
-            gd, build_ref = sb_info[repo, ref]
             if (repo, ref) == (root_repo, root_ref):
                 spec['repo'] = None
                 spec['ref'] = None
diff --git a/morphlib/plugins/branch_and_merge_plugin.py b/morphlib/plugins/branch_and_merge_plugin.py
index a258cd70..133c1d1f 100644
--- a/morphlib/plugins/branch_and_merge_plugin.py
+++ b/morphlib/plugins/branch_and_merge_plugin.py
@@ -309,6 +309,7 @@ class BranchAndMergePlugin(cliapp.Plugin):
                 cached_repo = lrc.get_updated_repo(chunk_url)
 
                 gd = sb.clone_cached_repo(cached_repo, chunk_ref)
+                gd.set_config('morph.chunk-name', chunk_name)
                 system_branch_ref = gd.disambiguate_ref(sb.system_branch_name)
                 sha1 = gd.resolve_ref_to_commit(chunk_ref)
 
diff --git a/yarns/branches-workspaces.yarn b/yarns/branches-workspaces.yarn
index de9f95a3..e77d2611 100644
--- a/yarns/branches-workspaces.yarn
+++ b/yarns/branches-workspaces.yarn
@@ -224,6 +224,15 @@ build branch is made to include that change.
     AND  the user builds systems/test-system.morph of the master branch
     THEN the changes to test-chunk in branch master are included in the temporary build branch
 
+It's also useful to be able to check out other branches to see the effect
+of building those changes instead.
+
+    GIVEN a different branch of test-chunk to build from
+    WHEN  the user checks out the different branch of test-chunk in branch master
+    AND   the user builds systems/test-system.morph of the master branch
+    THEN  the state of the current branch of test-chunk in branch master is included in the temporary build branch
+    AND   test-chunk of branch master's tree was used in the most recently built system
+
 ### When branches are created ###
 
 It's convenient to have Temporary Build Branches, but we don't always
@@ -397,6 +406,34 @@ Nor do we need temporary build branches for distributed builds.
             --format='git cat-file -p %(refname):test-bin | diff test-bin -' \
             "$build_ref_prefix")"
 
+    IMPLEMENTS GIVEN a (\S+) branch of (test-chunk) to build from
+    cd "$DATADIR/gits/$MATCH_2"
+    git checkout -b "$MATCH_1"
+    sed -i 's/Hello/Farewell/g' test-bin
+    git add test-bin
+    git commit -m 'Change message of test-bin'
+
+    IMPLEMENTS WHEN the user checks out the (\S+) branch of (\S+) in branch (\S+)
+    chunkdir="$(slashify_colons "test:$MATCH_2")"
+    cd "$DATADIR/workspace/$MATCH_3/$chunkdir"
+    git remote update
+    git clean -fxd
+    git reset --hard HEAD
+    git checkout "$MATCH_1"
+
+    IMPLEMENTS THEN the state of the current branch of (\S+) in branch (\S+) is included in the temporary build branch
+    chunkdir="$(slashify_colons "test:$MATCH_1")"
+    cd "$DATADIR/workspace/$MATCH_2/$chunkdir"
+    eval "$(git for-each-ref --count=1 --shell --sort=committerdate \
+            --format='test "$(git rev-parse HEAD^{tree})" = %(tree)' \
+            "$build_ref_prefix")"
+
+    IMPLEMENTS THEN (test-chunk) of branch (\S+)'s tree was used in the most recently built system
+    chunkdir="$(slashify_colons "test:$MATCH_1")"
+    cd "$DATADIR/workspace/$MATCH_2/$chunkdir"
+    artifact="$(ls -t "$DATADIR/cache/artifacts/"*.system.*-rootfs | head -n1)"
+    tar -xf "$artifact" -O usr/libexec/test-bin | diff test-bin -
+
     IMPLEMENTS WHEN the user commits changes to (\S+) in branch (\S+)
     chunkdir="$(slashify_colons "test:$MATCH_1")"
     cd "$DATADIR/workspace/$MATCH_2/$chunkdir"